Reorganization of brain-autonomic integration in alcohol use disorder.

Aberrant resting-state functional connectivity (rsFC) within neurocognitive networks is a hallmark of alcohol use disorder (AUD). However, the spatial architecture of the central autonomic network (CAN)-the vital neural substrate governing cardiovascular and homeostatic control-and its association with heart rate variability (HRV) remain poorly characterised. We investigated group differences in CAN-related rsFC and its statistical relationship with HRV metrics in 112 young adults (54 AUD, 58 healthy controls [HC]) using resting-state fMRI and separate, HRV assessments. Seed-based analyses targeted core cortical CAN nodes. Young adults with AUD exhibited a profound pattern of functional connectivity alterations within the CAN compared with HCs. Specifically, the AUD group demonstrated attenuated long-range connectivity between CAN seeds and temporo-frontal regions, alongside heightened, pathologically constrained intra-network connectivity involving the insula and brainstem. In HCs, resting HRV indices correlated positively with rsFC across widely distributed cortical and cerebellar systems, reflecting a robust baseline association between central CAN integrity and autonomic output. Conversely, the AUD group exhibited an attenuated and highly segregated pattern of relationships, where the expected association between CAN network architecture and resting HRV features was markedly diminished. These findings demonstrate that early-stage AUD is characterised by a fundamental spatial reorganization of the CAN and a significant blunting of brain-autonomic relationships. This neuro-autonomic alteration may represent a distinctive neuroimaging trait marker of chronic autonomic dysregulation, highlighting the critical need for early detection and targeted management of AUD in young adults.